Heating, ventilation, air conditioning and/or refrigeration (HVACR) systems typically have evaporator coils that are used in the cooling of air to be distributed by the system through the building or area to be cooled. These evaporator coils collect water formed by humid air which is condensed after contacting the cold metal on the evaporator coils. Water then drips from the coils into a drain pan usually placed beneath the air conditioning system. The drain pan typically has an outlet connected to a pipe, which directs it to a drain, sewer system, or an outside area where water can drip without damaging the building.
The drain line from the drain pan frequently clogs or plugs with “sludge” due to algae or fungus growing in the lines. When this happens, the water backs up into the drain line, fills the drain pan and overflows into the air supply duct. The water then spills out through any seam or hole available, and the overflowing water may cause considerable property damage, either from physical water damage or an electrical short. Therefore, the clogging of condensate drain lines is a considerable problem and can cause great concern to the homeowner, and typically an emergency call to the local heating and air conditioning service.
The experienced serviceman will recognize any condensate drain line plugging problem. The sludge is not a hardened mass difficult to remove. Rather, in the past such plugs have been readily removed by the serviceman connecting a high pressure source to the end of the drain line and blowing a short blast of gas up into the line. While this often dislodges the plug, it is typically ejected towards the inside A/C unit or drain pan, which can be messy and cause further damage to the unit or surrounding area.
Blockages also occur in other types of fluid-carrying lines, such as plumbing or toilet lines. Consequently, a variety of inventions are known in the art from such things as a plunger, sometimes called a plumber's helper, or a plumber's snake. Typically, these devices operate either by applying a mechanical or a hydraulic force to a blockage. However, condensate drain lines in HVACR systems are relatively small in diameter and are typically made of a more delicate material than water or sewage-carrying lines. Further, condensate drain lines may traverse relatively large distances from the inside air handler or evaporator coil where the condensation collects to the outside point where the condensation drains by means of the drain line. Consequently, things like plumber snakes or plungers are not helpful to clear blocked HVACR condensate drain lines.
Currently, an HVACR service technician has several options when confronted with a blocked drain line. He can clean out the drain pan and then apply air pressure within the drain pan end, or proximal end, of the drain line in hopes of clearing the blockage. However, this involves getting into a typically very small crawl space or attic in order to reach the drain pan area of the unit. The technician can also cut the drain line somewhere along its length in order to apply pressure or suction, which can lead to spillage from the drain line and require repair or partial replacement of the drain line after it is cut. For example, U.S. Pat. No. 5,666,690 to Domansky proposes inserting a CO2 powered cylinder into a cut drain line to clear blockages.
The technician can also apply pressure or suction at the drain end, or distal end, of the drain line. In the past, service technicians have been known to use their mouth to do this, with potentially unpleasant and/or unhealthy consequences. Also, a variety of different types of pumps that induce either a pressure or suction at the drain end of the drain line have been proposed for cleaning of drain lines. For example, U.S. Pat. No. 6,427,458 to Fowler discloses a pump having a cylinder that connects to the outside end of the drain line to create either a suction/vacuum or a positive pressure within the pump, which is communicated to the drain line for removing a blockage. U.S. Pat. No. 3,934,280 to Tancredi discloses a drain clearing device having a cylindrical body and a retractable piston plunger within. A flared flange is attached near the lower end of the cylindrical body to facilitate seating of the device onto a drain exit. Despite this work there is still a need for a simple and effective device to unblock or unclog a condensate drain line for HVACR systems.